Riluzole for motor neurone disease. More trials are needed.
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Clinical Trials as Topic↗
Biomedical subjects
S Bryan
Publications and source records attributed to S Bryan.
EQ-5D in patients with dementia: an investigation of inter-rater agreement.
BACKGROUND: There are difficulties in obtaining health-related quality of life (HRQL) data from patients with dementia due to variation in their cognitive ability, degree of insight and capacity to make judgments. The use of proxies is one solution. OBJECTIVES: To examine the inter-rater agreement of patient and proxy completion of the EuroQol EQ-5D instrument (EQ-5D). RESEARCH DESIGN: The EQ-5D instrument was completed separately by patients, their caregivers and a physician. Assessment of inter-rater agreement involved comparison of self-completed (patient) and proxy-completed (caregiver and physician) responses for each dimension of EQ-5D, using a weighted kappa score. Three key hypotheses were tested. (1) Interrater agreement would be stronger between patient and caregiver than between patient and physician. (2) Interrater agreement would be stronger on the 'observable' and objective dimensions of EQ-5D. (3) Interrater agreement between patient and proxies would be stronger for patients with earlier dementia. SUBJECTS: The sample comprised 64 patients with a range of dementia severity. MEASURES: The EQ-5D health state classification system and visual analogue scale were used to assess HRQL. Global severity of dementia was determined using the Clinical Dementia Rating Scale. RESULTS: The principal finding of this study was that responses to EQ-5D questions were highly variable across the three raters such that none of the three hypotheses were strongly supported. CONCLUSIONS: The data provide some support for the use of EQ-5D when interviewer administered. However, there are serious concerns regarding the validity of patient self-rated HRQL data obtained in this study and uncertainty exists regarding who the appropriate proxy should be, as different groups of proxies provide different results. It was not clear whether caregivers or physicians represent better proxies. Further research should focus on the comparison of caregivers and physicians as proxies.
Activities of Daily Living↗
The cost-effectiveness of magnetic resonance imaging for investigation of the knee joint.
OBJECTIVES: This study considered the role of magnetic resonance imaging (MRI) in the diagnosis of knee injuries in a district general hospital (DGH) setting. The principal objective was to identify whether the use of MRI had a major impact on the clinical management of patients presenting with chronic knee problems, in whom surgery was being considered, whether it reduced overall costs and whether it improved patient outcome. In addition, the research: (1) explored the 'diagnostic accuracy' of initial clinical investigation of the knee by an orthopaedic trainee, consultant knee specialist and consultant radiologist; (2) considered the variability and diagnostic accuracy of interpretations of knee MRI investigations between radiologists; (3) measured the strength of preference for the potential diagnostic/therapeutic impact of knee MRI (i.e. the avoidance of surgery). METHODS - RANDOMISED CONTROLLED TRIAL: The research was based on a single-centre randomised controlled trial conducted at Kent and Canterbury Hospital. Patients attending with knee problems in whom surgery was being considered were recruited from routine orthopaedic clinics. Most patients had been referred by their general practitioner. Patients were randomised to either investigation using an MRI scan (MRI trial arm) or investigation using arthroscopy (no-MRI trial arm). The study investigated the benefits of knee MRI at two levels: diagnostic/therapeutic impact (i.e. avoidance of surgery) and patient outcome (using the Short Form with 36 items and EQ-5D quality-of-life measurement instruments). Quality of life was assessed at baseline and at 6 and 12 months. Costs were assessed from the perspectives of the NHS and patients. All analyses were by intention to treat. METHODS - SUBSTUDIES (INVESTIGATION OF DIAGNOSTIC ACCURACY): For the investigation of diagnostic accuracy of initial clinical investigation, the sample comprised 114 patients recruited in a separate study conducted at St Thomas' Hospital. The sample was drawn from patients presenting at the Accident and Emergency Department with an acute knee injury. All study patients received an MRI scan, but initial diagnosis was made without access to the scan or the radiologist's report. After 12 months, all clinical notes and MRI scans of study patients were reviewed and a final 'reference standard' diagnosis for each patient was reached. Comparison was made between the diagnosis recorded by each clinician (i.e. orthopaedic trainee, knee specialist and consultant radiologist) and the reference diagnosis. METHODS - SUBSTUDIES (INVESTIGATION OF THE GENERALISABILITY OF RESULTS): For this substudy, the MRI images from 80 patients (recruited at St Thomas' Hospital) were interpreted independently by seven consultant radiologists at DGHs and the St Thomas' Hospital MRI radiologist. For each area of the knee, the level of agreement (measured using weighted kappa) between the responses of the eight radiologists and the reference standard diagnosis was assessed. METHODS - SUBSTUDIES (INVESTIGATION OF PREFERENCES): The investigation of potential patient preferences for the diagnostic/therapeutic impact of MRI was explored using a discrete choice conjoint measurement research design. Choices involved selecting between two alternative scenarios described using four attributes, and data were collected from 585 undergraduate sports science students and analysed using a random-effects probit model. RESULTS - RANDOMISED CONTROLLED TRIAL: The trial recruited 118 patients (59 randomly allocated to each arm). The two groups were similar in important respects at baseline. The central finding was of no statistically significant differences between groups in all measures of health outcome, although a trend in favour of the no-MRI group was observed. However, the use of MRI was found to be associated with a positive diagnostic/therapeutic impact: a significantly smaller proportion of patients in the MRI group underwent surgery (MRI = 0.41, no-MRI = 0.71; p = 0.001). There was a similar mean overall NHS cost for both groups. RESULTS - SUBSTUDIES (INVESTIGATION OF DIAGNOSTIC ACCURACY): The exploration of diagnostic accuracy found that, when compared to orthopaedic trainees (44% correct diagnoses) or to radiologists reporting an MRI scan (68% correct diagnoses), the accuracy rate was higher for knee specialists (72% correct diagnoses). RESULTS - SUBSTUDIES (INVESTIGATION OF THE GENERALISABILITY OF RESULTS): This generalisability study indicated that, in general terms, radiologists in DGHs provide accurate interpretations of knee MRI images that are similar to a radiologist at a specialist centre. The one area of the knee for which this did not hold was the lateral collateral ligament. RESULTS - SUBSTUDIES (INVESTIGATION OF PREFERENCES): The central finding for this substudy was that, on average and within the range specified, choices in this group of potential patients were not significantly influenced by variation in the chance of avoiding surgery. CONCLUSIONS - IMPLICATIONS FOR HEALTHCARE: The evidence presented in this report supports the conclusions that the use of MRI in patients presenting at DGHs with chronic knee problems in whom arthroscopy was being considered did not increase NHS costs overall, was not associated with significantly worse outcomes and avoided surgery in a significant proportion of patients. CONCLUSIONS - RECOMMENDATIONS FOR FURTHER RESEARCH (IN PRIORITY ORDER): (1) The trial data demonstrated that the use of MRI in patients with chronic knee problems reduced the need for surgery. However, the link between diagnostic processes and changes in health outcome is indirect and the finding of no-MRI-related effect on health outcome may, therefore, be a consequence of the limited power of the trial. Further research to confirm (or contradict) these findings would be valuable. (2) The investigation of diagnostic accuracy involved comparison with a reference diagnosis established by a panel of two clinical members of the research team. It would be interesting to explore the extent to which the results would differ using an external panel. (3) The result from the preference study, indicating that the potential diagnostic/therapeutic impact of knee MRI was not highly valued, is a surprising finding that would be important to explore in general public or patient populations. (4) The focus for the trial-based aspects of this research was the DGH and patients presenting with chronic knee problems who were being considered for surgery. Care should be taken in generalising from these results to other patient groups (e.g. acute knee injuries) or to other settings (e.g. specialist centres). Further clinical trials would be required in order to answer such questions.
Adolescent↗
Preference measurement using conjoint methods: an empirical investigation of reliability.
The application of conjoint measurement to the field of health economics is relatively new, although there is growing interest and there have been a number of studies undertaken recently. Wider acceptance of the technique requires methodological issues concerning both reliability and validity to be addressed. This paper reports an empirical investigation of the test-retest reliability of the discrete choice conjoint measurement approach in health care. This investigation of conjoint reliability was framed using the clinical context of investigation and treatment of knee injuries. A high level of reliability at both the input data and results levels was demonstrated.
Adolescent↗
A comparison of the time required by radiologists for the preparation of clinico-radiological meetings when film and PACS are used.
The hypothesis was that when a hospital-wide Picture Archive and Communications System (PACS) is used, preparation for clinico-radiological meetings is faster, and more images are available, than when a conventional film system is used. This paper reports a study which compared the preparation time by radiologists when film was used with the time for the same activity when a hospital-wide PACS was used at Hammersmith Hospital for the preparation of the respirator medicine and hepato-biliary meeting. It was found that when PACS was used the time per patient to prepare for the respiratory medicine session was reduced by 11.1 min and that similarly, 16 min per patient was saved in the preparation of the hepato-biliary sessions. The number of images which were unavailable for the session was reduced when PACS was in operation, but this reduction was not shown to be statistically significant. The introduction of PACS at Hammersmith Hospital has significantly reduced the time spent by radiologists in preparing for the two clinico-radiological sessions studied and, if this is extended to the other numerous sessions held each week, contributes to a considerable saving of staff time within the radiology department.
Communication↗
The impact of a picture archiving and communication system (PACS) upon an intensive care unit.
OBJECTIVE: The aim of the study was to assess the effect of the introduction of PACS (Picture Archiving and Communication System) upon image availability in an Intensive Care Unit (ICU) and the consequent impact upon the behaviour of the ICU physicians, in terms of the initiation of image-based clinical actions. DESIGN: A before and after study was used to compare the speed of image availability prior to, and following, the implementation of a hospital-wide PACS. SETTING: The research was part of an economic evaluation of PACS at Hammersmith Hospital, West London. PATIENTS AND PARTICIPANTS: All ICU patients who were X-rayed during two pre-PACS and one post-PACS data collection periods were included within the study. MEASUREMENTS: The times of: the X-ray request; acquisition; availability on ICU; and of any image-based clinical action taken by the ICU physician were recorded by radiographers and ICU physicians. RESULTS: PACS significantly reduced the time between request and image availability on ICU for routine X-rays but did not have any measurable impact upon the time clinical actions were initiated by ICU physicians. The data on non-routine images were statistically inconclusive. CONCLUSIONS: This study shows that PACS significantly improves the speed of delivery of routine images to the ICU, but it appears that the instigation of image-based clinical actions is determined by other organisational factors in ICU, such as ward rounds, rather than the availability of the image for viewing. Further work is required on non-routine X-rays to clarify the impact of PACS on physician behaviour in clinically urgent situations.
Humans↗
Estimating the impact of a diffuse technology on the running costs of a hospital. A case study of a picture archiving and communication system.
OBJECTIVES: This paper considers the methodological problems that arise in conducting cost analyses in economic evaluations where only observational (rather than experimental) data are available and where the technology being evaluated is diffuse, such that the unit of analysis has to be the institution rather than the patient. METHODS: A case study is reported that concerns the application of computer technology in radiology: picture archiving and communication systems (PACS). A range of different approaches were used to estimate changes in running costs, including time series analyses of routine data and direct observation of resource use. RESULTS: The analysis illustrates some of the difficulties involved in costing the introduction of a diffuse technology. Nevertheless, it provides a firm indication that, overall, the introduction of PACS was found to be associated with a significant increase in hospital costs, suggesting that the initial expectations of financial savings were unduly optimistic. CONCLUSIONS: The research demonstrates that, using multiple methods, it is possible to estimate cost changes within a single hospital. In addition, the paper discusses the nature of the uncertainties in such analyses and possible ways of representing such uncertainty in terms of confidence intervals.
Budgets↗
The effect of a picture archiving and communications system (PACS) on diagnostic performance in the accident and emergency department.
OBJECTIVE: A study has been conducted to identify the benefits to the accident and emergency (A&E) department of a hospital wide Picture Archiving and Communications System (PACS). METHODS: The study was conducted in two parts: firstly while the hospital was using conventional radiographic films, and secondly when the PACS was in operation. For each part of the study, the diagnoses of radiographic images made by A&E clinicians were compared with those made by radiologists. This resulted in the estimation of the incidence of false negative findings by the A&E staff. The management of patients with such findings was studied to identify those for whom a change of treatment was required. Such data for the two periods, when film and when PACS was used, were compared. RESULTS: It was found that the overall rate of misdiagnoses across all A&E patients who had radiography was low in both periods and there was a significant reduction when PACS was used (1.5% for film and 0.7% for PACS, 95% CI for difference between proportions: -0.014 to -0.0034), but the rate of serious misdiagnoses involving patient recall did not change significantly (95% CI for difference between proportions: -0.0059 to +0.0001). CONCLUSIONS: When PACS was used the diagnostic performance by A&E staff improved by reducing false negative interpretations but the rate of serious misdiagnosis did not change.
Diagnostic Errors↗
Comparison of doses for bedside examinations of the chest with conventional screen-film and computed radiography: results of a randomized controlled trial.
PURPOSE: To compare the radiation doses received by patients during bedside chest radiography when a computed radiography system was used and when a 400-speed screen-film system was used. MATERIALS AND METHODS: A randomized controlled trial was performed whereby all patients who were admitted to an intensive care unit were randomly assigned at admission to have all radiographic chest images obtained with either computed or conventional screen-film radiography. Doses were measured for 1 year, during which 269 patients underwent imaging. For these patients, surface entry doses were measured by means of individual thermoluminescent dosimeters placed on the skin at the center of the radiation beam. In addition, data were collected relating to the patient and examination characteristics, as well as to repeat examinations. Effective doses were calculated. RESULTS: The patients in the two arms of the study were well matched. The surface entry doses were higher in the computed radiography group (median, 0.21 mGy for computed radiography and 0.16 mGy for conventional radiography), and the effective doses were also higher (median, 0.036 mSv for computed radiography and 0.027 mSv for conventional radiography). Fewer examinations were repeated when computed radiography was used. CONCLUSION: When computed radiography was used, patient doses increased. The speed of this computed radiography system, which uses phosphor plate imaging, equates approximately to a 300-speed screen-film system.
Adolescent↗
Policy dilemmas for oral anticoagulation management.
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Anticoagulants↗
Humoral immunity to commensal oral bacteria in human infants: salivary secretory immunoglobulin A antibodies reactive with Streptococcus mitis biovar 1, Streptococcus oralis, Streptococcus mutans, and Enterococcus faecalis during the first two years of life.
Secretory immunoglobulin A (SIgA) antibodies reactive with the pioneer oral streptococci Streptococcus mitis biovar 1 and Streptococcus oralis, the late oral colonizer Streptococcus mutans, and the pioneer enteric bacterium Enterococcus faecalis in saliva samples from 10 human infants from birth to age 2 years were analyzed. Low levels of salivary SIgA1 and SIgA2 antibodies reactive with whole cells of all four species were detected within the first month after birth, even though S. mutans and E. faecalis were not recovered from the mouths of the infants during the study period. Although there was a fivefold increase in the concentration of SIgA between birth and age 2 years, there were no differences between the concentrations of SIgA1 and SIgA2 antibodies reactive with the four species over this time period. When the concentrations of SIgA1 and SIgA2 antibodies reactive with all four species were normalized to the concentrations of SIgA1 and SIgA2 in saliva, SIgA1 and SIgA2 antibodies reactive with these bacteria showed a significant decrease from birth to 2 years of age. Adsorption of each infant's saliva with cells of one species produced a dramatic reduction of antibodies recognizing the other three species. Sequential adsorption of saliva samples removed all SIgA antibody to the bacteria, indicating that the SIgA antibodies were directed to antigens shared by all four species. The induction by the host of a limited immune response to common antigens that are likely not involved in adherence may be among the mechanisms that commensal streptococci employ to persist in the oral cavity.
Antibodies, Bacterial↗
Evaluation of a hospital picture archiving and communication system.
OBJECTIVES: To establish the net costs to the hospital and the broad range of benefits associated with a hospital-wide picture archiving and communication system (PACS) that comprised digital acquisition, storage and transmission of radiological images via a hospital-wide network to 150 workstations. METHODS: 'Before and after' comparisons and time series analyses at Hammersmith Hospital (London, UK), and comparison with five other British hospitals where PACS was not being installed. The cost analysis considered implementation costs and changes in key elements of hospital running costs, including the impact of changes in the length of inpatient stays. A range of benefit measures were investigated, including image availability, avoidance of repeat imaging, avoidance of exposure to radiation, patient turn-round speed, time from examination to image availability in intensive care, avoidance of diagnostic 'errors' by casualty doctors, the additional diagnostic value of PACS-based images and clinician satisfaction. RESULTS: The annual equivalent capital cost of the PACS was 1.7 million Pounds (annual equivalent replacement cost: 0.8 million Pound). Overall, the PACS substantially increased running costs. No convincing evidence of a PACS-induced change in length of inpatient stay was found. PACS was associated with some improvements in the performance of the radiology department: improved image availability (97.7% versus 86.9%), lower repeat imaging rate (7.3% versus 9.9%) and 20% lower total radiation doses for examinations of the lateral lumbar spine. No improvements were identified in the quality of the radiology reporting service. Benefits outside radiology included shorter time from examination to image availability for routine uses in intensive care (19 versus 37 minutes), and a lower rate of diagnostic 'errors' in casualty (0.65% versus 1.51%). High levels of satisfaction with PACS were found amongst both providers and clinical users. CONCLUSIONS: PACS was almost universally preferred by users and brought many operational and clinical benefits. However, these advantages came at a significant capital and net running cost.
Cost-Benefit Analysis↗
The benefits of hospital-wide picture archiving and communication systems: a survey of clinical users of radiology services.
This paper describes one element of a broad evaluation of a hospital-wide picture archiving and communication system (PACS): an assessment of the views of users of the radiology service, their major causes of dissatisfaction with the service, the incidence of image unavailability, and the consequences of images being unavailable. The principal research design was a "before and after" comparison at Hammersmith Hospital, as the hospital site introducing PACS. Several other hospitals were included in this survey, for comparison. Questionnaires were distributed several times before PACS was operational at Hammersmith, and on one occasion after. The overall response rate was 54%. The main pre-PACS radiology-related problem areas were: the non-availability of images, the non-availability of written reports when clinically required, and the time devoted by junior staff to image searching. PACS greatly reduced the perceived problem of image non-availability. But Hammersmith's problems with the availability of radiological reports still remained when PACS was operational. The time junior doctors spent in image-searching was dramatically reduced by the introduction of PACS.
Attitude of Health Personnel↗
The effect of a picture archiving and communication system (PACS) on patient radiation doses for examination of the lateral lumbar spine.
This study was conducted to determine whether the doses for the radiographic examination of the lateral lumbar spine changed as a result of the introduction of a hospital-wide picture archiving and communication system (PACS). Doses were measured by thermoluminescent dosimeters (TLD) and dose-area product (DAP) meter readings for 100 patient examinations using a 300-speed conventional film/screen system and for 96 patient examinations when PACS was fully operational. Radiographic technique, exposure factors and patient characteristics were noted and effective doses were calculated, and a comparison was made of all variables. No significant differences between conventional and PACS working were found in surface entry and effective doses for single views of the lateral lumbar spine, but there was a 20% reduction in DAP readings with PACS. However, when summed doses for all images, including rejects, required to demonstrate the lateral lumbar spine for each patient were compared, PACS was found to be associated with significantly lower surface entry (TLD) dose, DAP reading and effective dose (28%, 36% and 16%, respectively) than conventional film. For single images of L1-5, when PACS was in use, there was a significant reduction in the DAP readings and increases in the area of the film/plate irradiated, the focus-to-skin distance and the focus-to-film distance. In addition, significantly fewer lumbosacral junction views were undertaken when PACS was in use. Since many confounding factors may have influenced the results over the period of dose measurement, regression models were used to determine the significance of PACS. These models showed that the use of PACS was not significant in causing any differences in the dose for single images as compared with when film was used, but was significant in the resulting total dose reductions for the examinations.
Adult↗
A comparison of image reject rates when using film, hard copy computed radiography and soft copy images on picture archiving and communication systems (PACS) workstations.
A comparison has been made of the reject rates of plain images for three separate periods when film, computed radiography (CR) and PACS systems were in operation throughout the Hammersmith Hospital, London. There was a statistically significant reduction in the overall percentage reject rate across all examinations from 9.9% to 8.1% when the hospital changed from using a conventional film based system to a CR system. There was a further reduction in the reject rate to 7.3% when the hospital moved to a hospital-wide PACS system, but this change was not statistically significant. Using estimations of the total number of images used, the percentage reject rates were 6.6% for film, 5.5% for CR and 5.5% for PACS. Thus, if the radiation dose for each image is unchanged, and the same types of images are used for the examination of each body area, a move from conventional film imaging to phosphor plate imaging provides the potential to reduce the patient population dose.
Computer Systems↗
Salmeterol for nocturnal asthma.
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Adolescent↗
Examining the influence of picture archiving communication systems and other factors upon the length of stay for patients with total hip and total knee replacements.
OBJECTIVES: To examine the influence of a picture archiving and communication system (PACS) on the length of stay (LOS) for patients receiving total hip replacement (THR) or total knee replacement (TKR) procedures. METHODS: A before-and-after design was used. Data were collected on all THR and TKR procedures at Hammersmith Hospital from 1993-96. A regression approach was used to examine the influence of PACS on LOS. Factors such as patient age, sex, and physician were controlled for. RESULTS: Type of admission and discharge, month of procedure, complications, and number of procedures all significantly influenced LOS for patients undergoing THR. For patients receiving TKR, age, sex, admission, prosthetic complications, number of procedures, and PACS significantly influenced LOS. CONCLUSIONS: While this study shows an apparent reduction of 25% in the average LOS for TKR patients at the time PACS was introduced, this is unlikely to be a true PACS effect and no similar reduction in LOS was shown for THR patients.
Aged↗
Magnetic resonance imaging for the investigation of knee injuries: an investigation of preferences.
The conventional approach to the diagnosis and treatment of severe knee injuries is arthroscopy, a minimally invasive surgical procedure. Since arthroscopy is an invasive technique that carries risks, magnetic resonance imaging (MRI) is increasingly being used for diagnosis. MRI is potentially associated with diagnostic and therapeutic 'impacts', in that arthroscopy can be avoided. This paper reports a discrete choice conjoint analysis exercise that assessed the value placed on such 'impacts' by potential patients and investigated the degree to which respondents were willing to trade between process and outcome. The marginal rates of substitution between attributes were estimated. The results suggest that the diagnostic and therapeutic 'impacts' of MRI were valued by many respondents. The study has highlighted a number of important issues for the design and analysis of future health-related conjoint studies, including the use of treatment cost as an attribute, dealing with data from lexicographic respondents, and distinguishing between points of indifference and missing data.
Adult↗